False twist assembly



United States Patent FALSE TWIST ASSEMBLY Joseph F. Lemieux, In,Manchester, N. assignor to L, M and L Corporation, Claremont, N.H., acorporation of New Hampshire Filed Dec. 30, 1957, Ser. No. 706,129

Claims. (Cl. 5751.6)

This invention relates to false twist devices used on spinning frames inthe textile fibre industry.

False twist devices have usually included an elongated tubular bodymember having a pair of diametrically opposed axially extending twisterpins at the upper end and yarn engaging means at the lower end. They arecustomarily mounted to rotate on a vertical axis in two fixed,vertically spaced bearings and a whirl or pulley is positioned on thebody member, between the bearings, for rotation by a belt. The upperpairs of draft rolls are usually located along the top of the frame andthe yarn engaging means of each false twist device is at a close spaceddistance above the nip of a pair of lower draft rolls located along theside of the frame. A strand to be drafted passes from the nip of a pairof upper rolls angularly over a fixed rod and then down into the axialbore, or central passage, of a false twist device and thence straightdownwardly into the yarn engaging means and the nip of the lower rolls.The lower rolls rotate at a greater surface speed than that of the upperrolls to attenuate, or draft the strand and the rotating pins of thetwist device impart a false twist to strengthen the strand duringdrafting.

The object of drafting devices of the prior art has generally been tomove the fibres in the strand steadily forward from the upper rollersand present the same in order to the front rollers whereby the yarn willbe a thinner copy of the strand with each fibre displaced an equalamount. However, textile strands are not always uniform in cross sectionand there are often thick places and thin places therein.

In this invention the principal object is to not only displace thefibres in a fibrous strand an equal amount in a drafting zone but toalso correct any irregularities in thickness of the strand in that zone.

Another object of the invention is to provide spring tension in apredetermined amount on a strand being drafted between two sets of draftrolls by resiliently supporting a unitary rotatable twister pin supportto automatically vary the axial distance between the pins and fixed yarnengaging means.

A further object of the invention is to eliminate the fixed deflectorrod over which the drafted strand is angularly bent in many spinningframes and to substitute therefor, a spring mounted, unitary, twisterhead and pins for creating such an angular bend, the pins risingresiliently when strand tension is temporarily reduced.

Still another object of the invention is the production of higherquality yarn from existing spinning frames by substituting a springloaded, unitary, veltical movable,

false twist head for the usual fixed false twist tube and deflector rodthereby overcoming one of the principal causes of uneven yarn.

A still further object of the invention is to provide a simple, ruggedfalse twist tube assembly in which both the upper and lower ends of thetube are provided with ceramic inserts for reducing wear and the entiretubular "ice wall in contact with the strand can be easily and quicklreplaced.

Other objects and advantages of the invention will be apparent from theclaims, the description of the drawing and from the drawing in whichFig. l is a fragmentary end view of a spinning frame showing, insection, a device according to this invention in the drafting zone.

Fig. 2 is a fragmentary view similar to Fig. 1 showing another positionof the false twist head member of the invention, and

Fig. 3 is an enlarged cross sectional view of the ceramic insert at thelower end of the head member.

The drafting zone of a well known type of spinning frame used in thewoolen system is shown in Fig. 1, the remainder of the frame being wellknown and forming no part of this invention.

A pair of upper, or feed, draft rolls 20 and 21 are mounted along thetop of the spinning frame 22, the rolls 20 and 21 having a nip 23 andbeing rotated at a predetermined surface speed by mechanism not shown.

A pair of lower draft rolls 24 and 25, having a nip 26 are mounted alongthe side of the frame and are rotated at a predetermined greater surfacespeed than rolls 20 and 21, by mechanism not shown.

A pair of vertically spaced apart bearings 27 and 28 are located betweenthe upper and lower draft rolls of such frames, the bearings being fixedto the frame 22 by a suitable element 29.

In the prior art a false twist tube has been mounted to rotate on itsvertical axis in bearings such as 27 and 28, without vertical movement,and a fixed deflector rod has been mounted on frame 22 along the top ofthe tubes around which the roping, roving or strand 31 has beenangularly bent before entering each tube.

In this invention the deflector rod is completely eliminated and thestrand 31 extends from the nip 23 directly into the top of the rotatingfalse twist assembly 32 and thence in a straight line downwardly throughthe device and into the nip 26 of the lower rolls.

The false twist assembly 32 includes an elongated tubular body member 33rotatable in the bearings 27 and 28 and having a whirl 34 sleevedthereon, the whirl having a set screw 35 for afiixing the same. Aflexible belt or band 36 is trained around each whirl such as 34 forrotating the same in the usual manner. The numeral 37 represents yarnengaging means of a well known type having a fixed jaw 38 and a pivotedjaw 39 the latter being oounterweighted at 40 and applying an increasinggrip to strand 31 by centrifugal force during rotation of assembly 32.The terminal tips 43 and 44 of jaws 38 and 39 are at a close spaceddistance from nip 26, this being the critical zone of drafting and thisdistance does not change, in this invention, in spite of the rise andfall of the twister pins.

Preferably the yarn engaging means 37 is attached to the body member 33by threads 45 and the top 46 of the body member is of enlarged diameterto form an integral, cylindrical cap 47. Cap 47 forms an annularexterior shoulder 48 resting on bearing 27 and a hollow cylindricalrecess 49 therewithin. The assembly 32 may thus be removed from thebearings 27 and 28 by unthreading the yarn engaging means 37, looseningset screw 35 and sliding the body member 33 upwardly out of thebearings. During use, the shoulder 48 and whirl 34 prevent any verticalmovement of the body member 33, thus maintaining the distance betweentips 43 and 44 and the nip 26 of lower rolls 24 and 25. The body member33 includes a straight axial bore 50, in continuation of recess 49 andextending down to the lower terminal end thereof.

The false twist assembly 32 includes a unitary false twist head member53 axially slideable in the bore 50 and rotatable with the body member33. Head member 53 preferably is provided with a cap 54 of enlargeddiameter and an integral shank 55 of reduced diameter, the cap 54slideably fitting within recess 49 and the shank 55 slideably fittingwithin bore 50. An annular shoulder 56 is thus provided under cap 54which rests on the bottom of recess 49 to form a limit stop and a hollowcylindrical recess 57 is formed within cap 54- in which an annular,ceramic twister pin insert 58 is detachably alllxed as by adhesives. Pininsert 58 is preferably of porcelain and provided with a pair ofdiametrically opposed, axially extending twister pins 59 and 60 as wellas an axial bore 61.

The shank, or integral extension 55 of head member 53 extends from thecap 54 down to a level below the lower end of body member 33 and justabove the jaws 33 and 39 and includes a straight, cylindrical, axialbore 64 in extension of the bore 61 of insert 58. An annular groove 65is formed in the head member 53 for a split, flexible, ring 67, the ringbeing detachable but serving as a stop to limit upward movement of headmember 53. A key or pin 68 is located on the exterior of shank 55 andslideable in a keyway 6), formed in bore 50, to permit axialslideability of the head member 53 while assuring rotation thereof withbody member 33. As shown in Fig. 1, the textile strand 31, being given afalse twist, is in engagement with insert 58 at one end of assembly 32and with yarn engaging means 37 at the other end of assembly 32. Thecylindrical bore 64 of shank 55, however, does not grip the strand butmerely guides and confines the strand in its path through the assembly32.

Resilient means preferably in the form of a coil spring 70 encirclingshank 55 of head member 53 is provided for continually urging the headmember 53 away from the yarn engaging means 37 under predeterminedspring pressure. Bore is counterbored to form a spring well 71constituting an annular space within body member 32 for accommodatingthe coil spring 70. Spring 70 at one end bears against the shoulder 56formed by the bottom face of cap 54 and at the other end bears againstthe annular shoulder 72 formed by the bottom of the spring well 71. Ifdesired another coil spring, or a plurality of coil springs, may beprovided in a suitable spring well to alter the characteristics of thedevice. It should be noted that the spring 79 is compressed only by thepressure exerted by the strand 31 so that it is responsive only tochanges in tension of the strand.

In Fig. 1 the twister pins 59 and 60 are shown rotating on thelongitudinal axis of assembly 32 which axis is angularly oifset from astraight line path between nips 23 and 26 of the two pairs of draftrolls. In full lines a strand of normal cross section is shown exertingnormal uniform tension on the spring 70 whereby the pins are resilientlyfloating about half way between their lowermost and uppermost positions.The rim 73 of insert 58 is creating the angular bend in the strand 31which would heretofore have been created by the fixed deflector rod ofthe prior art.

In dotted lines the strand 31 is shown as having an irregularityconstituted by a portion of thick cross section 74, such thickerportions usually being less taut than a thinner section and thus underdecreased tension. Under such conditions, the coil spring 70 raises thetwister pins 59 and 60 thereby making the angle of approach from nip 23slightly smaller, slightly increasing the length of the path of thestrand between the pairs of drafting rolls and slightly increasing thetime during which the pins successively jerk the strand during theirrotation. Such treatment tends to reduce the cross section of thethickened strand portion to the normal cross section and when completedthe spring 70 is compressed again to its normal position.

In Fig. 2 a thin portion of strand 31 is shown, such thin portionsusually being extra taut with fibres in closer frictional engagementwith each other than in a strand of normal cross section. The additionaltension created by the thin portion 75 tends to compress spring 70 thuslowering pins 59 and 60. The path of the strand between nips 23 and Z6is thus shortened to slightly relieve tension and the change of angle atrim 73 slightly reduces the bite of the pins to also reduce the timeduring which the rotating pins jerk the strand.

As shown in Fig. 3 because the terminal end 76 of shank 55 is constantlyrising and falling relative to yarn engaging means 37, the insidediameter thereof at '77 is enlarged and a ceramic insert 78 fixedtherein as by adhesive. The lower rim 79 of insert 78 is rounded andpreferably both insert 78 and insert 58 are of porcelain.

It has been found that the slidability of the head member 53, and thepredetermined spring load thereof away from the yarn engaging means 37,tends to reduce the breakage of strands during the spinning operation.This is probably for the reason that the spring means 70 serves as acushion to gradually compensate for any weak portions in the strand anddoes not permit sharp changes in tension thereon.

I claim:

l. A false twist device for use in textile fibre spin ning machines,said device comprising a unitary false twist head member having astraight cylindrical, axial bore and diametrically opposed pinsextending axially from the upper end thereof, a false twist body memberhaving a straight cylindrical axial bore and adapted to be rotatablearound its axis, said head member being axially slideable in the boreof, and rotatable with, said body member, yarn engaging means at thelower end of said body member, and spring means between said head andbody members continually urging said head member axially away from saidyarn engaging means but yieldable in the opposite axial direction forresponding to variations in tension exerted by a textile strand on saidhead member.

2. A combination as specified in claim 1 wherein said false twist bodymember is an elongated tube having a whirl removably fixed therearoundand said false twist head member is an elongated tube having an annularceramic insert at the upper end thereof and an annular ceramic insert atthe lower end thereof, said pins being integral with said upper ceramicinsert.

. 3. A combination as specified in claim 1 wherein said spring means isa coil spring encircling said unitary head member and located in theaxial bore of said body member, said body member includes an annularshoulder in said bore for seating one end of said spring means and saidhead member includes an annular shoulder for seating the opposite end ofsaid spring.

4. A false twist assembly for use in textile fibre spinning frames, saidassembly comprising an elongated tubular body member having a whirldetachably sleeved therearound and adapted to be rotated around itslongitudinal axis; yarn engaging means afiixed to the lower end of saidbody member; an elongated unitary, tubular hea d member rotatable withsaid body member, said head member having an annular ceramic top withintegral upstanding twister pins thereon and having a straight tubularshank extending axially through said tubular body member to a levelproximate said yarn engaging means and axially slidable in said bodymember, said shank and body member forming an annular spacetherebetween, and a coil spring encircling said shank in said annularspace and arranged to continually urge said head member upwardly withpredetermined pressure but to yield downwardly under greater pressureexerted by a textile strand.

5. A combination as specified in claim 4 plus corresponding annularshoulders on said head and body members for limiting downward axialmovement of said head member, and a split ring detachably mounted in anannular groove in said head member for limiting upward axial movement ofsaid head member.

during upward and downward movement of saidhead member relative to saidyarn engaging means.

7. A combination as specified in claim 4 plus threads on the lower endof said body member and corresponding threads on said yarnengaging meanswhereby said yarn engaging means is threadedly removable from said bodymember.

8. In a spinning frame the combination of upper and lower draftingrolls; a pair of spaced bearings fixed to said frame between said upperand lower rolls; 'a false twist assembly rotatably mounted insaidbearings for rotation around a longitudinal axis angularly olfsetfrom a straight line between the nips of said upper and lower rolls,said assembly including a tubular body member having yarn engaging meansat the lower end thereof delivering a strand into the nip of said lowerrolls, a unitary, tubular head member having twister pins thereon, saidhead member being axially slideable in, and rotatable with, said bodymember, and resilient means connecting said bodyrnember to said headmemher, said resilient means continually urging said head member axiallyaway from said yarn engaging means for varying the angle of approach of.said strand to said pins and varying the length of strand between saidupper and lower draft rolls in accordance with variations'in tensionofsaid strand at said pins.

9. A'combination as specified in claim 8 wherein said resilient meanscomprises at least one coil spring encircling, and resiliently bearingagainst, said head member at one end and encircled by, and resilientlybearing against, said body member at the opposite end thereof.

10. A combination as specified in claim 8 plus a whirl detachablysleeved on the exterior of said tubular body member for rotating thesame; an enlarged integral top onsaid body member and on said headmember proximate the pin portion thereof, and mechanism for detachingsaid yarn engaging means from said body member for enabling theslideable removal of said whirl from said body member.

References Cited in the file of this patent UNITED STATES PATENTS2,846,730 .Abbott Aug. 12, 1958

